U.S. Pat. No. 7,165,871 B2 describes a lamp for generating light which comprises a semiconductor light emitting element for emitting light, a fluorescent material, provided away from the semiconductor light emitting element, a first optical member operable to focus the light generated by the semiconductor light emitting element on the fluorescent material, and a second optical member having an optical center at a position where the fluorescent material is provided, operable to emit light from the fluorescent material based on the light focused by the optical member to an outside of the lamp. The lamp is used as a headlamp in a vehicle, and the second optical member emits the light from the fluorescent material to the outside of the lamp, so that the second optical member forms at least one of a part of a cut line that defines a boundary between a bright region and a dark region of the headlamp. This document further describes the combination of a laser, a phosphor and a reflector integrated into a light emitting module used for automotive front light applications. Such lasers usually deliver pencil-shaped beams originating from a small spot and showing little divergence. Very local heat dissipation in the fluorescent material appears and thus limits the brightness of such a lamp.
During the last decades, light emitting diodes, LEDs for short, have become more and more important in lighting applications due to the advances of semiconductor technology. High-power LEDs have opened the door to new lighting concepts comprising miniaturization, lifetime, efficiency and sustainability of the optical elements.
Lasers show a much higher brightness than LEDs. Semiconductor lasers showing output powers in the range of several Watts are available and thus enable a high lumen output. Currently, laser pumped optical lamps for different potential lighting applications are investigated. It is expected that they show a high potential for dedicated lighting applications such as spots for automotive, architectural indoor, outdoor and accent lighting.
However, there is a need to utilize the strong quality of lasers comprising their high brightness and keeping their optical performance as high as possible in conjunction with solving the above-mentioned thermal issue problem.